Cisco VPN Fix
I live with the OS X Cisco VPN client running nearly non-stop, and occasionally get this frustrating error:
Error 51: Unable to communicate with the VPN subsystem. Please make sure that you have at least one network interface that is currently active and has an IP address and start this application again.
Happily, Rob Griffiths at Macworld has a solution:
sudo SystemStarter restart CiscoVPN
No more rebooting! Yay!